This invention relates in general to wheelchairs. More particularly, this invention relates to wheelchair frames. Most particularly, the invention relates to adjustable wheelchair frames.
Wheelchairs are well known forms of transportation that increase the mobility of the physically impaired. Wheelchairs are typically relatively small, single-person conveyances that generally comprise a seat supported by a frame which, in turn, is supported by two oppositely disposed drive wheels and two front casters.
The wheelchair occupant's center of gravity is generally positioned near the axle position of the drive wheels to permit the wheelchair occupant to maneuver the wheelchair with greater ease. The wheelchair occupant's center of gravity may be shifted in a number of ways. The drive wheels may be cambered so that the distance between the drive wheels at ground level is greater than the distance between the drive wheels at the seat. In addition to cambering the drive wheels, adjusting the position of the drive wheels relative to the wheelchair frame may also shift the wheelchair occupant's center of gravity. For example, the drive wheels may be moved forward or backward, or may be raised or lowered, relative to the wheelchair frame to shift the wheelchair occupant's center of gravity.
Adjusting the wheelchair seat relative to the wheelchair frame may also shift the center of gravity of the wheelchair occupant. In addition to shifting the center of gravity of the wheelchair occupant, adjusting the wheelchair seat may improve the orientation of the arms and hands of the wheelchair occupant relative to the drive wheels. Improving the orientation of the arms and hands of the wheelchair occupant relative to the drive wheels enables the occupant of the wheelchair to propel the wheelchair with greater comfort and increased efficiency. Optimal positioning of the wheelchair seat also reduces the risk of tissue trauma suffered by the wheelchair occupant by reducing the constant pressure between the wheelchair occupant's skin and the wheelchair, and particularly, the wheelchair seat.
A need exists for a simplified assembly for adjusting the angle of inclination of wheelchair seat in accordance with the physical characteristics of the wheelchair occupant and further in accordance with various purposes for which the wheelchair is used.